Science

Pollen Records Indicate Ancient 'Thousand-Year' Drought

This winter is shaping up to be among the Bay Area's driest on record, but scientists are weighing the odds of a thousand-year drought.

Some researchers may have found one in ancient times -- something on the order of 1800 to 2800 years ago.

Paleoecologist Scott Mensing says that's a "long time ago from human perspectives, not long ago geologically".

Mensing is a paleo-ecologist at the University of Nevada, Reno. He turned up the evidence by studying ancient pollens buried in lake beds: not literally a thousand years with no rain, but a long, dry period, perhaps punctuated with a few wet intervals, centered in eastern Nevada but likely spreading into parts of California.

Could it happen again? "If there is this potentially hundreds-to-thousand-year-long dry period, it shows you what the system is naturally capable of," says Mensing. "But what ocean conditions or other drivers actually set the stage for this millennium drought, is something that needs more research."

Mensing reported his findings at this week's Pacific Climate Workshop in Pacific Grove.